How to generate random numbers between 0 and 1 in bash

I'm trying to infer how to generate two random numbers as input values for parameters of readproportion, updateproportion in a way that sum of these parameters should equal 1, in the following bash command.

$ ./bin/ycsb run basic -P workloads/workloada -p readproportion=0.50 -p updateproportion=0.50

Please help with your suggestions.

Thanks